The most common and most likely answer to this crossword clue is the 3 plus 4 letter word BOW LEGS
I've seen this crossword clue in The Times
B
O
W
L
E
G
S
More clues leading to the result BOW LEGS
Buddy explains!

The straight part
We know that "Curved pins" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case curved pins = bow legs.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.